Numerical Investigation on the Effect of Section Width on the Performance of Air Ejector with Rectangular Section

Area of Science:

• Fluid Dynamics
• Aerospace Engineering
• Mechanical Engineering

Background:

• Supersonic air ejectors are vital in machinery, aerospace, and energy-saving applications due to their simple design.
• Ejector performance is constrained by flow channel geometry and jet velocity, with confined jets being a key limitation.
• Understanding the influence of confined geometry is crucial for optimizing supersonic air ejector efficiency.

Purpose of the Study:

• To numerically investigate the effect of section width (W) on the performance of a rectangular section supersonic air ejector.
• To analyze the impact of W on entrainment ratio, velocity, turbulent kinetic energy, Mach number, and vorticity distributions.
• To elucidate the role of geometric confinement and flow structures in the ejector's mixing process.

Main Methods:

• Design of a rectangular section supersonic air ejector for numerical simulation.
• Computational fluid dynamics (CFD) analysis to study the effects of varying section width (W).
• Examination of flow field parameters including entrainment ratio, velocity, turbulent kinetic energy, Mach number, and vorticity.

Main Results:

• The entrainment ratio (ER) increased by 91.2% as section width (W) expanded from 1 mm to 10 mm.
• Increasing W led to an expansion of the turbulent kinetic energy region, indicating enhanced mixing.
• Streamwise vortices significantly contributed to the mixing process, with their distribution increasing with W.

Conclusions:

• Section width (W) is a critical parameter influencing supersonic air ejector performance, particularly the entrainment ratio.
• Geometric confinement in the rectangular section and the XOY plane affects internal fluid flow and mixing.
• Optimizing section width and understanding vortex dynamics are key to improving supersonic air ejector efficiency.